Can you give more details? I'm on 09 so considering upgrading at some point.
Sure,
The layout is similar on the left panel, however now- when you right click a photo there are far less options available. I remember if you had duplicates for instance, you could right click any photo in the library and find the original in finder- that option is gone.
Faces works better- I will give them that.
Places, improved looks but nothing more.
The layout in the Photos window has changed to a grouping of sorts, yet they are labeled like the old folders used. Problem is, i can't find for the life of me how to change any labeled untitled event.
Really, to be honest, some may like it better for Full Screen mode; however I don't really care for it, nor use it at all. I really find iPhoto used for a library of sorts like iTunes. I think the new version has taken away many tweaks or options that 09' had, But- if it has not lost old tweaks etc, I certainly am having a hell of a time finding them.
I have actually been using it for about 3 weeks on and off, and I am going to go back.
Only thing I like better is you can Upload, email, etc to different media outlets like Flicker/facebook, etc. However like I mentioned above I have had zero success sending a MM gallery to anyone including myself without it arriving in a spam box for some reason- and using my MM address.
Bottom Line, I dislike it. But, YMMV